CHAPTER 4Using the Gateway168Analog InputThe analog input is provided for connecting analog sensors deliv-ering a voltage of 0 - 2.5V or a current of 4 - 20 mA converted to avoltage to the analog pins of the connectors.Note: The "4 - 20mA" setting assumes that you use the AdconA502 current-to-voltage converter which converts a currentof 4 - 20mA to a voltage of 0.4 - 2.0V. If you want to use adifferent converter, you have to select "0 - 2.5V" as sensortype and manually calculate the proper “conversion range"settings to reflect the physical values the sensor would havefor converted voltages within the range of 0 and 2.5V.Pulse CounterThis type of sensor can be used, e.g., to measure the rotationspeed of an engine or to count the hits on a target.Digital I/OA digital I/O allows to connect digital sensors as well as digitallycontrolled actuators.Digital sensors deliver measurements in form of binary datastreams to the digital pin of the connector.Digital actuators are driven by binary data streams provided by thedigital pin of the connector. An actuator is a mechanical or electri-cal device for moving or controlling a mechanism or system. Theactuator is usually a physical mechanism but also refers to an artifi-cial agent.Internal InputMost RTUs, the Wireless Modems and the Gateways are (or can be)equipped with built-in sensors (“internal sensors”). These sensorsserve especially the purpose to watch the battery or supply voltageas well as the internal temperature of the respective devices. Bydefault, the actual values of these sensors do not correspond tothe definitions displayed in the “State information” windows. If,however, the output of these sensors is to be recorded, it is neces-sary to define these internal sensors as separate sensor types. Bythat, the measurements can be evaluated as those from any othersensor.
